Detection system for the location of moving objects

ABSTRACT

Radio signals generated from a transmitter mounted on a moving object are induced into a plurality of crossed pairs of lines and into a reference pair of parallel lines. The difference in phase between the signals induced in the crossed pairs and reference pair of lines is used precisely to identify the location of the moving object.

United States Patent Kurauchi et a].

[451 Sept. 16, 1975 DETECTION SYSTEM FOR THE LOCATION OF MOVING OBJECTS Inventors: Noritaka Kurauchi; Kenichi Yoshida; Yoshinobu Kobayashi; Masataka Kuroda, all of Osaka, Japan Assignee: Sumitomo Electric Industries, Ltd.,

Osaka, Japan Filed: Feb. 6, 1974 App]. No.: 440,217

Foreign Application Priority Data Feb. 8, 1973 Japan 48-15824 Feb. 8, 1973 Japan 48-15825 US. Cl. 340/23; 246/63 C; 246/122 R;

340/38 L; 340/47 Int. Cl. G08G 1/12 Field of Search 246/63 C, 122 R, 187 B;

[56] References Cited UNITED STATES PATENTS 3,609,676 9/1971 Charleroi 340/23 3,740,549 6/1973 Thorme-Booth..... 246/122 R v 3,786,41 1 H1974 Kurauchi et a1. 340/47 X Primary ExaminerMaynard R. Wilbur Assistant Examiner-Richard E. Berger Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT Radio signals generated from a transmitter mounted on a moving object are induced into a plurality of crossed pairs of lines and into a reference pair of parallel lines. The difference in phase between the signals induced in the crossed pairs and reference pair of lines is used precisely to identify the location of the moving object.

2 Claims, 7 Drawing Figures r) IQ PATENTEDSEPISIQYS 3.906.436

SHEET 1 0F 2 ABCDEF PHASE DIFFERENCE RELATIVE LOCATION OF MOVING OBJECT FIG. 2

FIG. 3

PATENTED SEP I 6 I975 SE; WEEK 6 5:22

' LOCATION .OF MOVING OBJECT B l c n 1 IIIlIII'II have been widelyiused for detecting locations of obsince they have nomechanical contact parts and are less disturbed by external noises.

A system for detecting locations in accordance with receiving signal levels has been utilized so far-in which several pairs'of lines are employed and the higher re ceivingsignal level state and the lower receiving signal level state are encoded was to correspond respectively to binary l and O; In this system, however, satisfactory accuracy-for the'location detection can not be achieved because of fluctuation of receiving signal levels, for example.- i i SUMMARY 055ml; INVENTION The object of this invention is to overcome the fore-. going defects and provide a system for detectingfllocations of a moving object with high accuracy. The presects moving on a certainltrack suchiascranes or trains,

ent invention is a system for detecting absolute address iv location of a moving object by the use of inductive radio,"comparingthe phase' of the signals which. are transmitted from the moving object and induced 'in crossing pairs of lines with that of the signal whichis transmitted from the moving object and induced in a reference pair oflines."

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 is a schematic diagram showing'one embodiment of the invention; 1

FIG. 2 is a chart showing the relation between the 10-. cations of the moving object (on abscissa) and relative phase difference (on'ordi'nate) received on one crossing pair of lines in the system shown in FIG. 1; .i FIG. 3 is a chart showing the waveform'shaping performedin the system of the invention; 1

located in the direction along which the object moves. The length of each address is represented as 1 Ina pair of lines 1 which cross each other periodically at every 21 of length, the crossing points thereof 11 11 11 coincide respectively to theaddress boundaries of adjacent pairs of addresses. In another pair of lines 1 which .cross each other periodically at every 41 of length, the crossing points 11 11 11 respectively coincide to the address boundaries between adja cent sets of four addresses and located between said crossing points 11 and 11 11 and 11 respectively of said pair of lines 1 Fora further pair of lines 1 which cross eachother periodically at every 81 of length, the crossing points thereof 11 1.1 11 also coincide respectively to the address boundaries between adjacent sets of eightqaddres'ses and located be tween said crossing points of 11 and 11 11 and 11 .-respectively. 1

Pi Thus, n. pairs of crossing lines are used, each pair of lines has a crossing period of 2'! X 1,, the crossing points in each of the pairs of lines coincide to the location of the address boundaries of every 2" addresses, and they i for the transmitting signals from the generator 6. Usually, coiled antennas are used for antennas 5 and 5 and each of the coils 5 and 5 is located corresponding to each of the positions of the conductors of thepair of lines;

It is of course possible to attain the performance of this invention by using only either one of said coiled antennas 5 and 5 or antennas having other configurations.

i In the figure, are shown amplifiers 7 7 7 7 "7 connected respectively to one end of (n 1) pairs of 'linesl l 1 1 ,;1,, waveform shaping cirsii zwssi each vof said amplifiers, n exclusive OR circuits 9,, 9

F IG. 4 is a schematic diagram'showing another embodiment of the invention;

FIG. 5-is a graphical representation showing the relation of the locations of the moving object (on abscissa) to the amount of phase shift (on ordinate), FIG. 6 (a) is a schematic diagram showing the principle of still another embodiment of the invention;

FIG. 6 (b is a graphical representation showing the relation of the locations of the moving object to the amount of phase shift (curve a compared with the relation obtained in the embodiment of FIG. 4 (curve a );and 7 l FIG. 7 is a schematic diagrarnshowing further em bodiment of'the inven tion; i a

PREFERRED EMBODIMENTS THE INVENTION H This inventioil will he described in detail referring to the accompanying drawing.

FIG. 1 shows a preferred embodiment of thisiriven: l i

9 9,, connected to each of said waveform shaping circuits and a register 10; connected to said exclusive OR circuits and storing (n bits of information. i

High frequency signals fro'mthe generator 6 mounted on the moving object are induced in. each of the (h i' 1) pairs of lines through the antennas 5. The signals in- "formula:

i( o B 2 i i t in which'P represents the amplitude, [3 is a phase constant and- 2 represents a distance alongthe direction of themoving object.

mitted to theamplifier 7 shown in FIG. 1 are represented by the formula:

tion and letters/8,8, C, D, E, denoteaddresses. i

. S 8 connected respectively to I It can be seen from the comparison of the formulas (1) and (2) that the terms regarding the phase in each of the formulas are BZ and B2 rr/2l Z line and the difference between their phases changes by 1r, that is 180, every time the antennas of the moving object pass through the crossing points of the pair of conductor lines 1 Accordingly, the difference between the phase of the signals in the pair of lines 1 and that of the parallel pair in lin 1,, at the ends of the pairs of lines is zero when the antennas of the moving object are situated at the left of the address A and is 180 when the antennas are situated at addresses A and B. In the same way, the difference in the phase again is zero when the antennas are situated at addresses C and D received signals at the ends of the crossing pair of lines 1 and the parallel pair of lines 1 it quite similarly .becomes zero when the antennas are situated at the left of and on the address A and becomes 180 when the antennas are situated at each of the addresses B, C, D and E, and becomes again zero when they are situated behind the address F. In this way, the phase difference of the received signal at the end of each of the n-th crossing pair of lines and one parallel pair of lines alternatively takes the values of zero and 180 at every crossing point. v

The phase differences of zero and 180 respectively correspond to binary numbers 0 and fl as shown in table 1 and each address is represented by the binary gray code.

The signals received at the end of each pair of lines are amplified through the amplifier circuits 7,,- 7 7 7 and, thereafter, converted from the sinusoidal into square waveform as shown in FIG. 3 by way of the waveform shaping circuits 8,, 8 8 8 When the output signals from the waveform shaping circuit 8,, and those from each of the waveform shaping circuits 8,, 8 8,, are inputted to the exclusive- OR circuits 9,, 9 9 the output level of the exclusive-OR circuits becomes a high level if the two input signals are in the same phase (zero phase difference) and becomes a low level if they are in the opposite phase (180 phase difference).

The register connected with n exclusive-OR circuits stores the signals of binary O or high level information, and binary 1 or low level information, and the address at which the moving object is present can be identified by the contents of the register.

Referring now to another example of this invention in FIG. 4, reference numeral 12 denotes a pair of lines periodically crossed at a fundamental crossing interval of a, the end of which is connected with a receiver 13.

Antennas 15 and 15 mounted on a moving object 14 are connected to a transmitter 18 andarranged perpendicular to the line 12 and an antenna 16 is arranged in parallel with said lines 12 and connected to another transmitter 18 via a phase shifter 17 which shifts the phase in an amount of When the moving object 14 travels along the pair of lines 12, the coupling between the antennas 15 and 15 'and the pair of lines disappears instantaneously at the crossing points of lines, and the signal level repeats the substantially sinusoidal change along the lines. The coupling between the an tenna l6 and the pair of lines provides the maximum signal level at the crossingpoints of the pair of lines 12 and disappears at the midpoint between adjacent crossing points thereby repeating the sinusoidal change in a similar way. I

Therefore, when the signals induced from the antennas 15 and 15 and signal induced from the antenna 16 are added to one another and simultaneously received by the receiver 13, a constant signal level can be attained irrespective of the locations of the antennas, and

the'embodiment-in FIG. 4 in which no crossing points are-eliminated, it can be seen that the curve a-, shifts in phase below the curve a by the amount of 11' in the vicinity of the location 4a for the moving object, because no phase changes areproduced in the parallel portion due to the lack of crossing point's.

Based on the foregoing, it is possible to eliminate the crossing points in pair of lines 2 12 at any desired positionand to render the portion parallel thereby varying the phase by and identifying the location by detecting the variation.

FIG. 7 is an schematic view for illustrating the construction of the embodiment of this invention based on the foregoingprinciple, wherein a pair of lines 21 intersect at a fundamental crossing interval: of a and absolute addresses are constituted with section A, B,'C, having length of I and including-a plurality of said fundamentalcrossing intervalsv a;.T he pair of lines 21 are formed by .prepa ring parallel sections 31 31,

inating the crossing point at every interval of 4l The relation between the pair lines 21 and 21 is keptin such a way that the parallel section of the latter, for example, 31 lies between the parallel sections, for example.3l and 31, of the former,

Generally, the n-th pair oflines 21 has crossing points on every fundamental crossing interval of a and parallel sections 31, 31,, formed by eliminating said crossing points on every 2" .l with such relation to the pair of lines 2l,, that the parallel section 31,. is placed between the parallel sections 31,, and 31,... of the lines 21,,

i The pair of lines 21 21,, are respectively con-' nected to the exclusive-OR circuits 24 24,, by way of receiving amplifiers 22, 22, and waveform shaping circuits 23 23 and the pairof line 21 which provides the reference phase as indicated as a curve a, in FIG. 6 above, is connected to the exclusive-OR circuits 24 24,, in parallel with the inputs for said respective pair of lines 21 21,, via a receiving amplifier 22,, and a waveform shaping circuit 23, In the figure, 25 denotes a register circuit connected to the output of the exclusive-OR circuits.

The address on which the moving object is present can be detected as follows. High frequency signals from the object on any of the sections A, B, C, are induced in each of said pair of lines 21 21 The output signals amplified and shaped respectively by amplifiers and waveform shaping circuits are inputted to the exclusive-OR circuits 24 24,, and are compared in phase with that of the output from the reference pair of line 21,, also amplified and shaped in a similar way, thereby generating a binary if they are in same phase and l if they are in opposite phase, which are then stored in the register 25.

The embodiment shown in FIG. 7, when compared with that in FIG. 1, can reduce the difference in the phase constant between each of the pair of lines by crossing the pair of lines at a closer interval (at interval of a), as well as having the advantage of reducing the mutual induction coupling between each of the pairs of lines and induction from external noises. It is also possible by counting the numbers of the fundamental crossing interval a to detect a finer location in each of the addresses A, B, C,

What is claimed is:

1. A system for detecting the absolute address location of a moving object by the use of inductive radio comprising;

1. n pairs of crossing pairs of lines each having crossing period ofl X 2" (n= 1, 2, 3, and by which all of the addresses of 2" locations can be represented in a manner different with each other, the unit length of the addressbeing l 2. a parallel pair of lines which is not crossed;

3. means for generating high frequency signals mounted on the moving object;

4. an antenna supplied with high frequency signals from said high frequency generating means and electromagnetically coupling said signals to said n pairs of crossing pair of lines and one parallel pair of lines;

5. (n l) circuits'which are connected respectively to the ends of said n pairs of crossing pairs of lines and said one parallel pair of lines, and receivng and amplifying high'frequency signals;

6. n phase detectors which are connected to said receiving and amplifying circuits and comparing the phase of the signal received on each crossing pair of lines and that on the parallel pair of lines; and

7. registers connected to said phase detectors and storing binary signals 1 and 0 corresponding respectively to the state in same phase or in the opposite phase; thereby comparing the phase of the signals, induced from said moving object and received by said n pairs of crossing pairs of lines with that received on said one parallel pair of lines to detect the binary coded absolute address.

2. A system for detecting the absolute address locations of a moving object by the use of the inductive radio comprising;

1. a reference crossing pair of lines crossing periodically of length a;

2. n pairs of crossing pairs of lines in which the crossing points with period of a are eliminated at the address boundaries on every interval of l X 2" (n l, 2, 3 1 address length) and by which all of the addresses less than 2' are represented in a way different from each other;

3. means for generating high frequency signals mounted on the moving object;

4. an antenna supplied with the high frequency signals from said high frequency signal generating means and coupling electromagnetically to said n pairs of crossing pair of lines and to one reference crossing pair of lines;

5. (n l) circuits connected respectively to the ends of said n pairs of crossing pairs of lines and one reference crossing pair of lines and receiving and amplifying the high frequency signals;

6. n phase detectors connected to said receiving and amplifying circuits and comparing the phase of the signal received on one reference crossing pair of lines with that of the signal received on each of said n crossing pairs; and

7. registers connected to said phase detectors and storing the binary signals 1 or 0 corresponding to the state in the same phase or in the opposite phase respectively, thereby comparing the phase of the high frequency signals, induced from said moving object and received on said n pairs of crossing pairs of lines with that received on said one reference crossing pair of lines to detect the binary coded absolute address. 

1. A system for detecting the absolute address location of a moving object by the use of inductive radio comprising;
 1. n pairs of crossing pairs of lines each having crossing period of l1 X 2n (n 1, 2, 3, . . .) and by which all of the addresses of 2n locations can be represented in a manner different with each other, the unit length of the address being l1;
 2. a parallel pair of lines which is not crossed;
 3. means for generating high frequency signals mounted on the moving object;
 4. an antenna supplied with high frequency signals from said high frequency generating means and electromagnetically coupling said signals to said n pairs of crossing pair of lines and one parallel pair of lines;
 5. (n + 1) circuits which are connected respectively to the ends of said n pairs of crossing pairs of lines and said one parallel pair of lines, and receivng and amplifying high frequency signals;
 6. n phase detectors which are connected to said receiving and amplifying circuits and comparing the phase of the signal received on each crossing pair of lines and that on the parallel pair of lines; and
 7. registers connected to said phase detectors and storing binary signals ''''1'''' and ''''0'''' corresponding respectively to the state in same phase or in the opposite phase; thereby comparing the phase of the signals, induced from said moving object and received by said n pairs of crossing pairs of lines with that received on said one parallel pair of lines to detect the binary coded absolute address.
 2. a parallel pair of lines which is not crossed;
 2. A system for detecting the absolute address locations of a moving object by the use of the inductive radio comprising;
 2. n pairs of crossing pairs of lines in which the crossing points with period of a are eliminated at the address boundaries on every interval of l1 X 2n (n 1, 2, 3 . . . , l1 address length) and by which all of the addresses less than 2n are represented in a way different from each other;
 3. means for generating high frequency signals mounted on the moving object;
 3. means for generating high frequency signals mounted on the moving object;
 4. an antenna supplied with high frequency signals from said high frequency generating means and electromagnetically coupling said signals to said n pairs of crossing pair of lines and one parallel pair of lines;
 4. an antenna supplied with the high frequency signals from said high frequency signal generating means and coupling electromagnetically to said n pairs of crossing pair of lines and to one reference crossing pair of lines;
 5. (n + 1) circuits connected respectively to the ends of said n pairs of crossing pairs of lines and one reference crossing pair of lines and receiving and amplifying the high frequency signals;
 5. (n + 1) circuits which are connected respectively to the ends of said n pairs of crossing pairs of lines and said one parallel pair of lines, and receivng and amplifying high frequency signals;
 6. n phase detectors which are connected to said receiving and amplifying circuits and comparing the phase of the signal received on each crossing pair of lines and that on the parallel pair of lines; and
 6. n phase detectors connected to said receiving and amplifying circuits and comparing the phase of the signal received on one reference crossing pair of lines with that of the signal received on each of said n crossing pairs; and
 7. registers connected to said phase detectors and storing the binary signals ''''1'''' or ''''0'''' corresponding to the state in the same phase or in the opposite phase respectively, thereby comparing the phase of the high frequency signals, induced from said moving object and received on said n pairs of crossing pairs of lines with that received on said one reference crossing pair of lines to detect the binary coded absolute address.
 7. registers connected to said phase detectors and storing binary signals ''''1'''' and ''''0'''' corresponding respectively to the state in same phase or in the opposite phase; thereby comparing the phase of the signals, induced from said moving object and received by said n pairs of crossing pairs of lines with that received on said one parallel pair of lines to detect the binary coded absolute address. 